One of the first things to know about juniper berry essential oil is that the juniper berry it comes from is not a berry. Rather, it's more like a small pine cone than a berry. And in fact, it’s not even really a fruit but a spice – a bitter citrus-tasting one, to be exact. The berry or cone starts small and green and eventually turns bluish-black in its second year of growth. In late spring, small flowers bloom on the juniper plant. 
Juniper berry has been used since ancient times for a medicinal, culinary, and spiritual purpose. The Old Testament includes several references to the Juniper Tree. As far back as 1500 BCE, Egyptians use juniper berries to cure tapeworms. Romans used them to aid digestion. Even the Greeks got on the juniper berry bandwagon, giving them to athletes to boost their physical stamina.
While on duty, medieval physicians chewed juniper berries and burned the hospitals' branches because doing so helped ward off contagious diseases. In World War II, the French returned to burning juniper in hospitals as an antiseptic when their drug supply ran low. Here in North American, Native Americans used juniper berries for medicinal applications and burned the berries to cleanse and purify the air.
And thanks to juniper berry, many today can enjoy a gin and tonic on a warm summer night. In the 17th Century, William III reigned over England, taxed beer and cider to encourage imports of a distilled malt wine called jenever from his Dutch homeland. English distillers added juniper to Jenever to make it more palatable. In response to demand for juniper-flavored spirits, English distillers started making their own version of a predominantly juniper-flavored spirit called gin.
Juniper Health Benefits
Juniper berry essential oil is made by steam distillation of the crushed, dried, or fermented berries. Among its many properties for health and wellness, juniper berry essential oil is a strong antioxidant. It also is a well-known antiseptic; acts as an astringent; promotes and improves circulation, helps removes toxins like uric acid from the body so that it can help to fight rheumatism and arthritis; relieves cramps; treats stomach issues, speeds up healing of wounds, and detoxifies the blood. 
Juniper berry essential oil is made up of monoterpenes, including limonene, camphor, and beta-pinene. Monoterpenes have been shown to provide anti-inflammatory, anticancer, antioxidant, and antibacterial properties.
Benefits for Aromatherapy and Massage
Used in aromatherapy, juniper berry essential oil can have a calming effect on stress and anxiety and lift the spirits and boost energy. When used in a massage, it may help to soothe sore muscles and joints and improve circulation. Its antibacterial properties also can help to reduce skin irritations.
 Masters, Susanne, “Juniper,” Distiller, October 1, 2016. https://distilling.com/distillermagazine/juniper/
 Christiansen, Sherry, “The Health Benefits of Juniper Berries.”
 Höferl, M.; Stoilova, I.; Schmidt, E.; Wanner, J.; Jirovetz, L.; Trifonova, D.; Krastev, L.; Krastanov, A. Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. The action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism. Antioxidants 2014, 3, 81-98. https://doi.org/10.3390/antiox3010081
 Nagdeve, Meenakshi, “13 Incredible Benefits of Juniper Essential Oil,” Organic Facts, August 7, 2020. https://www.organicfacts.net/health-benefits/essential-oils/health-benefits-of-juniper-essential-oil.html
 Kubala, Jillian, MS., RD., “5 Emerging Benefits of Juniper Berries,” Healthline, August 30, 2019. https://www.healthline.com/nutrition/juniper-berries